Micrometer-calipers.



ZECI-IARIAH R. TUCKER, 0F PROVIDENCE, RHODE ISLAND.

MICROMETER-CALIPERS.

Specification of Letters Patent.

Application filed May 12, 1909.

Patented May 31, 1910.

Serial No. 495,461.

To all whom it may concern:

Be it known that I, ZEoHaniAii R. TUCKER, a citizen of the UnitedStates, residing at Providence, in the county of Providence and State ofRhode Island, have invented certain new and useful Improvements inMicronieter-Calipers, of which the following is a specification.

My invention relates to novel improvements in measuring devices andattachments such as micrometer gages, calipers and similar mechanismsand has for its objects the ends commonly sought in this class ofstructures, but more particularly to provide in a single instrumentmeans for taking such measurements as have heretofore necessitated theemployment of a plurality of instruments; to minimize the danger offalse readings and wear of the parts; and to insure accuracy of results.

My invention consists in the application of principles hereinafter setforth, and includes such novelty as is embraced in the claims at the endof the specification.

In the drawings which form a part of this specification, Figure 1 is aside elevation of al pair of micrometer calipers embodying my invention,a portion being broken away, Fig. 2, a bottom plan View of the same, andFig. 3, a section on line 3 3 of Fig. 1.

Like characters of reference indicate like parts throughout the views.

In its present form of embodiment my measuring instrument comprises aframe 1 whose lower portion is cut away as at 2 to form integralparallel arms 3 and 4 upon its forward and rear ends respectively. Theforward part of the frame is upwardly eX- tended in alinement with thearm 3 to form a iXed jaw portion 5. Extending through the end of theportion 5 of the frame is the measuring spindle 7 of an ordinary pair ofmicrometer calipers whose graduated barrel S is fixed to the portion 5and is disposed longitudinally of the frame, carrying the usual milledsleeve or thimble 9. Slidably mountedin openings 10 and 11 of the arms 3and 4 respectively and longitudinally of the frame is a bar 12 providedupon its end with a jaw portion 13 extending at right angles to the barand preferably provided at its end with the usual anvil 14 in alinementwith the spindle 7. In the lower eX- tremities of the arms 3 and 4 arescrews 16 and 17 respectively which are in clamping engagement with thebar 12 or with gibs or bearing plates 18 and 19 rest-ing against the bar12 in openings 10 and 11. Slidably mounted upon the rod 12 intermediatethe arms 3 and 4 is a member 20, in the present instance a block,provided upon opposite sides of its upper portion with hardened bearingpoints 21 and 22, and having mounted in its lower portion a clampingscrew 23 adapted to engage the bar 12 or a gib or bearing plate 24resting against the bar. The leg 3 is, if desired, provided with abearing point 25 in the path of the point 21, and the arm 4 has in itsupper port-ion in the path of point 22 a screw 26 having a hardened end27, the whole constituting an adjustable contact point. The screw 26 islocked in position by a screw 28 in the frame. The b-arrel 8 and thimble9 are respectively provided with the usual reading line 29 and scale 30.

The space intermediate the points 25 and 27 less the distance betweenthe faces o-f the points 21 and 22 is exactly equal to the full traverseof the spindle 7 as indicated on the barrel 8, in this instance oneinch.

While the points 21, 22, 25, and 27 are convenient for preventing wear,and the member 26 for taking up wear, these parts are not essential.

In the present instance the bar 12 carries a jaw 13, but it is obviousthat the jaw portion may be removably connected with the bar, or may beof proper contour or dimensions to form a base, or the bar may carry anyother attachment usual or convenient for facilitating the taking ofmeasurements, and the structure may be used as a height or depth gage,or as a substitute for a vernier caliper.

To use my device the thimble 9 is screwed back its full limit of oneinch or other unit of measurement, in the present instance one inch. Ifdesired, the spindle 7 may now be clamped by a set screw 31 in the frameor by any other convenient means for preventing accidental turning ofthe spindle. The screws 16, 17, and 23 are then loosened, and both theframe and block 2O are moved along the bar 12 until the faces of thespindle 7 and anvil 14 contact with each other. One or both of screws16, 17 are tightened and the block 2O moved until its point 22 abutsagainst the point 27, whereupon the screw 23 is tightened to temporarilyprevent the movement of block 20. Next screws 16 and 17 are againloosened and the frame longitudinally advanced until the point 25 abutsagainst the point 21, bringing the parts into the position shown in Fig.l, and thereby opening a space between the anvil and spindle thedistance of the measuring unit. Again the frame is clamped, and theblock advanced the limit of its travel and clamped, and the frame movedup into contact therewith. This adds a second unit to the space betweenthe anvil and spindle. The described steps may be repeated an indeiinitenumber of times thereby increasing the measuring capacity of theinstrument many fold beyond the measuring limit of the spindle.Measurements of fractions of a unit are obtained in the usual manner byturning the thimble 9.

In this structure Will be noted the absence of graduated scales or linesother than those on the barrel and sleeve, thereby avoiding the errorsarising from inaccurate readings and Wear involved in the use ofinstruments of the Vernier type which involve a comparison of lines.

What I claim is,-

1. In a measuring instrument, the combination With a frame, of amicrometer mounted upon the frame, arms upon the frame, a bar slidablymounted in the arms, a jaW upon the bar in coperative relation to themicrometer, and a slidable member adjustably mounted upon the barintermediate the arms and movable upon the bar a distance equal to themeasuring capacity of the micrometer.

2. In a measuring instrument, the combination with a frame, of amicrometer mounted on the frame, arms upon the frame, a bar slidablymounted in the arms, a aw upon the bar in cooperative relation to themicrometer, clamping members in the arms, a slidable member upon the barintermediate the arms, and a clamping member upon the slidable member. v

In testimony whereof I have affixed my signature in presence of twoWitnesses.

ZECI-IARIAI-I It. TUCKER.

Witnesses LEONARD IV. IhIoRToN, HonATro E. BELLoWs.

